2
HIGH ALTITUDE CONVERSION
1. Shut OFF gas supply at manual shutoff and turn OFF power to the furnace.
2. Remove access door.
3. Disconnect wiring from the gas valve.
4. Remove the gas manifold assembly by removing the four screws connecting it to the burner bracket. See Figure 2 below.
Figure 2 - Gas Manifold Removal
5. Remove factory installed orifices from gas manifold using 7/16" box end wrench.
For Natural Gas Operation, complete steps 6 & 7; For L.P. Gas Operation, complete steps 8 through 13.
6. Visually inspect the high altitude Natural Gas orifices (B2589907) for damage and drill size (#49) before installation.
Install orifices and tighten with a box-end wrench, take care to avoid cross threading or over tightening.
7. Attach the gas manifold assembly to the burner bracket using the four screws removed in step 4.
8. Visually inspect the high altitude L.P. Gas orifices (B2589908) for damage and drill size (#56) before installation. Install
orifices and tighten with a box-end wrench, take care to avoid cross threading or over tightening.
9. Remove the “NAT. GAS” label from the top of the 36J27 gas valve.
10. Use needle nose pliers to place the jumper (see enclosed F92-1021 kit) on the receptacle. Make sure both pins engage the
jumper.
11. Place the “L.P.” label (see the enclosed F92-1021 kit) on the gas valve, covering the jumper installed in step 8.
12. Attach the “WARNING” label (see the enclosed F92-1021 kit) to the gas valve where it can be readily be seen.
13. Attach the gas manifold assembly to the burner bracket using the four screws removed in step 4.
GAS SUPPLY PRESSURE CHECK
Gas Supply Pressure must be verified with all appliances in operating mode. See Table 2 for the required gas pressure.
1. Turn OFF electrical power & gas supply to the unit.
2. Use 3/16" Allen wrench to remove 1/8" inlet pressure tap from the gas valve.
3. Connect a calibrated water manometer or appropriate gas pressure gauge at the gas valve inlet pressure tap.
4. Turn ON the power and gas, put the unit into heating cycle on high fire (100%) to verify proper supply pressure. If gas
supply is not within the range specified, contact your gas provider.
Manifold
Gas Valve
4 Screws
